U.S. patent application number 12/190929 was filed with the patent office on 2009-01-29 for sealing apparatus and gas turbine having same.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Kuniaki AOYAMA, Kiyoshi FUJIMOTO, Hiroaki KISHIDA.
Application Number | 20090026713 12/190929 |
Document ID | / |
Family ID | 38495896 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090026713 |
Kind Code |
A1 |
FUJIMOTO; Kiyoshi ; et
al. |
January 29, 2009 |
SEALING APPARATUS AND GAS TURBINE HAVING SAME
Abstract
It is an object of the present invention to provide a sealing
apparatus having high sealing performance, entailing a low cost,
and satisfactory in assembly characteristics. The sealing apparatus
is a differential pressure-responsive sealing apparatus which is
inserted between seal grooves formed in the side surfaces of outlet
flange portions of adjacent combustor transition pipes to seal
clearance between the side surfaces, comprising: a minimum required
number of seal pieces connected in the longitudinal direction for
imparting flexibility, the seal piece comprising a heat resistant,
wear resistant material, and having a pair of sealing ridges each
having an arcuate surface contacting the wall surface of each seal
groove.
Inventors: |
FUJIMOTO; Kiyoshi;
(Takasago-shi, JP) ; KISHIDA; Hiroaki;
(Takasago-shi, JP) ; AOYAMA; Kuniaki;
(Takasago-shi, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW, SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
38495896 |
Appl. No.: |
12/190929 |
Filed: |
August 13, 2008 |
Current U.S.
Class: |
277/543 ;
415/230 |
Current CPC
Class: |
F16J 15/0887 20130101;
F01D 9/023 20130101; F05D 2240/57 20130101 |
Class at
Publication: |
277/543 ;
415/230 |
International
Class: |
F16J 15/26 20060101
F16J015/26; F04D 29/08 20060101 F04D029/08 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 2006 |
JP |
2006-041012 |
Claims
1. A differential pressure-responsive sealing apparatus which is
inserted between seal grooves formed in end surfaces of adjacent
members to seal clearance between the end surfaces, comprising: a
minimum required number of seal pieces connected in a longitudinal
direction for imparting flexibility, the seal piece comprising a
heat resistant, wear resistant material, and having a pair of
sealing ridges each having an arcuate surface contacting a wall
surface of each seal groove.
2. The sealing apparatus according to claim 1, wherein a plurality
of the seal pieces formed by machining or press-working are
connected by a flexible sheet joined to the seal pieces while
spanning flat side surfaces of the seal pieces.
3. The sealing apparatus according to claim 1, wherein the seal
pieces formed by press-working to have the sealing ridges of a
semi-annular cross section are laminated in a superposed manner,
and a plurality of the seal pieces laminated are tied together by
wires each inserted into a circular hole formed by two of the
sealing ridges opposing each other.
4. The sealing apparatus according to claim 1, wherein a sealing
metal foil is interposed between connecting surfaces of the seal
pieces.
5. The sealing apparatus according to claim 2, wherein a sealing
metal foil is interposed between connecting surfaces of the seal
pieces connected in the longitudinal direction.
6. The sealing apparatus according to claim 3, wherein a sealing
metal foil is interposed between connecting surfaces of the seal
pieces connected in the longitudinal direction.
7. A gas turbine in which a seal between gas turbine combustors at
outlets of the gas turbine combustors is constructed using the
sealing apparatus according to claim 1, 2, 3 or 4.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a sealing apparatus, and a gas
turbine having this apparatus. More particularly, the invention
relates to a sealing apparatus for sealing clearance between
assembly components which changes owing to external force or
thermal expansion or the like, for example, a sealing apparatus
suitable as a seal between gas turbine combustors at their
outlets.
[0003] 2. Description of the Related Art
[0004] Generally, a gas turbine has an air compressor (may
hereinafter be referred to as "compressor"), a combustor, and a
turbine as main constituents. The combustor is disposed between the
compressor and the turbine connected together directly by a
rotating shaft. Air to serve as a working fluid is taken into the
compressor in accordance with the rotation of the rotating shaft,
and compressed there. The compressed air is introduced into the
combustor, and burned with a fuel. The resulting combustion gas at
a high temperature and a high pressure is ejected to the turbine to
drive the rotating shaft as well as the turbine rotationally. Such
a gas turbine is effectively used as a drive source for a power
generator or the like which is connected to the front end of the
rotating shaft.
[0005] In recent years, a low NO.sub.x (premix) combustor has been
used frequently from the aspect of pollution control over air
pollution, etc. With the low NO.sub.x (premix) combustor, a larger
amount of combustion air is needed for decreasing NO.sub.x. Thus, a
sealing apparatus is applied to each part of the gas turbine to
manage air leakage strictly.
[0006] Examples of the sealing apparatus used as a seal between gas
turbine combustors at the outlets of the combustors are shown in
FIGS. 5 to 7.
[0007] FIG. 5 shows a brush seal 102 used as a seal between gas
turbine combustors at the outlets of the combustors (i.e., a side
seal). The brush seal 102 comprises a rail 102a to be fitted into a
groove formed in a wall portion of one of transition pipes, and a
wire brush 102b whose leading end is pressed against the back of a
flange portion of the other transition pipe and which is composed
of wires densely planted in the rail 102a. The brush seal 102 is
adapted to reduce air leakage from the casing side to the turbine
side.
[0008] FIG. 6 shows a so-called worm seal 104 comprising many
I-shaped punched-out pieces 104a tied in a row with the use of a
flexible sheet 104b. The worm seal 104 seals clearance between
flange portions of adjacent transition pipes, thereby reducing air
leakage from the casing side to the turbine side. The worm seal 104
serves for sealing when it is inserted into grooves formed in the
adjacent transition pipes, and a pair of arcuate projections 104ab
of the worm seal 104 are pressed against the wall surfaces of the
grooves under a differential pressure between the casing and the
interior of the combustor.
[0009] FIG. 7 shows a sealing apparatus for sealing clearance
between connecting surfaces (opposing surfaces) of the end surface
of one component 106A and the end surface of other component 106B.
This sealing apparatus is mounted in a space portion between
groove-shaped stepped portions formed in the connecting surfaces.
The sealing apparatus comprises a sealing body 107 composed of a
support portion 107A having a first seal protrusion 107A1 in
intimate contact with a second step surface 106A2 of the one
component 106A and a second seal protrusion 107A2 in intimate
contact with a second step surface 106B2 of the other component
106B, and a holding portion 107B formed to be upright on the
support portion 107A; a first seal member 108 having a second side
portion 108C secured to the side surface of the holding portion
107B, a curved elastic portion 108B, and an inclined first side
portion 108A, the second side portion 108C, the elastic portion
108B, and the first side portion 108A being formed in the shape of
a U-plate; a second seal member 109 disposed on the side surface of
the holding portion 107B in symmetrical relation with the first
seal member 108, having a second side portion 109C secured to the
side surface of the holding portion 107B, and having nearly the
same configurational requirements as those of the first seal member
108; a first seal surface 108A1 in intimate contact with a first
step surface 106A1 of the one component 106A at an outward surface
of an end portion of the first side portion 108A of the first seal
member 108; and a second seal surface 109A1 in intimate contact
with a first step surface 106B1 of the other component 106B at an
outward surface of an end portion of the first side portion 109A of
the second seal member 109. As noted above, end sides of the second
side portions 108C and 109C are secured to the holding portion
107B. In this manner, the assembly clearance between the components
where a high temperature fluid flows, or the assembly clearance
between the components involving vibrations can be always sealed
(see JP-A-2005-76802).
[0010] However, the seal shown in FIG. 5 has posed the problem that
the deformation of the wire brush 102b at the time of combustor
assembly and after operation of the gas turbine is marked, arousing
a concern about deterioration of performance, so that the seal is
difficult to apply to a low NO.sub.x (premix) combustor. That is,
the wire brush 102b may collapse or wear when the clearance changes
at the time of combustor assembly, during operational vibrations,
or at start or stoppage of the gas turbine. There has also been the
problem that the cost for repair of the combustor increases because
of replacement work necessitated by deformation after
operation.
[0011] With the seal shown in FIG. 6, higher sealing performance
than that of the brush seal 102 in FIG. 5 has been confirmed.
However, increases in processing man-hours and the number of the
components have presented the problem of cost increases.
[0012] The sealing apparatus shown in FIG. 7 has involved the
problems that an increase in the number of the components results
in a cost increase, and the sealing body 107 is integrally formed,
and lacks flexibility, leading to poor assembly characteristics
within a narrow space.
SUMMARY OF THE INVENTION
[0013] The present invention has been accomplished in light of the
above-described situations. It is an object of the invention to
provide a sealing apparatus having high sealing performance,
entailing a low cost, and satisfactory in assembly characteristics,
and a gas turbine equipped with the sealing apparatus.
[0014] A first aspect of the present invention is a differential
pressure-responsive sealing apparatus which is inserted between
seal grooves formed in end surfaces of adjacent members to seal
clearance between the end surfaces, comprising: a minimum required
number of seal pieces connected in a longitudinal direction for
imparting flexibility, the seal piece comprising a heat resistant,
wear resistant material, and having a pair of sealing ridges each
having an arcuate surface contacting a wall surface of each seal
groove.
[0015] A plurality of the seal pieces formed by machining or
press-working may be connected by a flexible sheet joined to the
seal pieces while spanning flat side surfaces of the seal
pieces.
[0016] The seal pieces formed by press-working to have the sealing
ridges of a semi-annular cross section may be laminated in a
superposed manner, and a plurality of the seal pieces laminated may
be tied together by wires each inserted into a circular hole formed
by two of the sealing ridges opposing each other.
[0017] A sealing metal foil may be interposed between connecting
surfaces of the seal pieces, i.e., the seal pieces connected in the
longitudinal direction.
[0018] The present invention can realize the sealing apparatus
which has a small number of the components, whose production is
easy, and which is wear resistant. Thus, the sealing apparatus has
high sealing performance, and can achieve cost reduction.
Furthermore, the flexible sheet can impart moderate flexibility,
and thus can enhance assembly characteristics.
[0019] A second aspect of the present invention is a gas turbine in
which a seal between gas turbine combustors at outlets of the gas
turbine combustors is constructed using the above-mentioned sealing
apparatus.
[0020] The gas turbine of the present invention enables the
performance of a low NO.sub.x (premix) combustor to be fully
exhibited.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The present invention will become more fully understood from
the detailed description given hereinbelow and the accompanying
drawings which are given by way of illustration only, and thus are
not limitative of the present invention, and wherein:
[0022] FIG. 1 is a schematic configurational drawing of essential
parts of a gas turbine showing Embodiment 1 of the present
invention;
[0023] FIG. 2 is a perspective view of essential parts of a sealing
apparatus in the gas turbine;
[0024] FIG. 3 is a plan view of a sealing apparatus showing
Embodiment 2 of the present invention;
[0025] FIG. 4 is a configurational drawing of a sealing apparatus
showing Embodiment 3 of the present invention;
[0026] FIG. 5 is a configurational drawing of a conventional brush
seal;
[0027] FIG. 6 is a configurational drawing of a conventional worm
seal; and
[0028] FIG. 7 is a configurational drawing of a conventional
further different sealing apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] A sealing apparatus, and a gas turbine using the apparatus,
according to the present invention will be described in detail by
the following embodiments with reference to the accompanying
drawings.
Embodiment 1
[0030] FIG. 1 is a schematic configurational drawing of essential
parts of a gas turbine showing Embodiment 1 of the present
invention. FIG. 2 is a perspective view of essential parts of a
sealing apparatus in the gas turbine.
[0031] As shown in FIG. 1, a gas turbine has a plurality of (e.g.,
16) combustors 1 of a low NO.sub.x (premix) type arranged around a
main shaft (rotating shaft; not shown). In each combustor 1, a fuel
F injected from fuel nozzles 3 provided adjacent to a combustor
inner tube 2, and compressed air PA ejected from an air compressor
(will hereinafter be referred to simply as a compressor) 4 and
introduced to the upstream side of the combustor inner tube 2 are
mixed. Then, the mixture is burned in a combustion region on the
downstream side of the combustor inner tube 2 or the upstream side
of a combustor transition pipe 5, and is introduced into a turbine
6 as a high temperature, high pressure combustion gas CG. In the
turbine 6, this combustion gas CG is sequentially passed through
and expanded by a plurality of turbine stages each comprising a
stationary blade 7 and a moving blade 8 to generate power, thereby
driving the compressor 4 as well as outputting a surplus drive
force to the outside.
[0032] The ratio between the compressed air PA and the fuel F
(air-fuel ratio) introduced into the combustor inner tube 2 needs
to be controlled to an optimal value in conformity with the
operating state of the gas turbine (i.e., the amount of the fuel
introduced). For this purpose, not all of the compressed air PA is
introduced into the combustion region of the combustor 1, but part
of the compressed air PA is bypassed and flowed from a casing 9
into the combustor transition pipe 5. A bypass valve 10 is provided
for this purpose and, by its action, part of the compressed air PA
is flowed and supplied into the combustor transition pipe 5 through
an opening of a bypass pipe 11 provided within the casing 9.
[0033] In the present embodiment, a sealing apparatus 20 as a seal
between the combustors (side seal) is interposed between outlet
flange portions 5a and 5a of the adjacent combustor transition
pipes 5. That is, seal grooves 5b of a rectangular cross section
are formed to oppose each other, in the side walls of the adjacent
combustor transition pipes 5. The sealing apparatus 20 is loosely
fitted between these seal grooves 5b and 5b.
[0034] The sealing apparatus 20 comprises a plurality of (2 to 4;
in the illustrated example, 3 or more) seal pieces 21 of the same
shape connected in the longitudinal direction, as shown in FIG. 2.
Concretely, a sealing metal foil 22 is interposed between
connecting surfaces of the respective seal pieces 21, and the seal
pieces 21 are coupled by a sheet 23 which is spot-welded (W) to the
respective seal pieces 21 while spanning their flat side surfaces,
and which is shorter than the seal piece 21 and has
flexibility.
[0035] On the side surface of each seal piece 21 on the side
opposite to the flat side surface thereof, sealing ridges 24 of a
semicircular cross section extend in the longitudinal direction at
right and left portions of the seal piece 21 in the drawing. The
seal piece 21 is manufactured by machining or press-working a heat
resistant, wear resistant alloy material such as Highness-25
(commercial name). The seal piece 21 may be provided with a wear
resistant coating (chromium carbide or the like), as is the
aforementioned seal groove 5b. The length of the sealing apparatus
20 is set to be nearly equal to the height of the outlet flange
portion 5a of the combustor transition pipe 5. The above-mentioned
sheet 23 is manufactured from the same material as that for the
seal piece 21.
[0036] Because of the above features, the sealing apparatus 20 is
inserted into the seal grooves 5b between the outlet flange
portions 5a of the adjacent combustor transition pipes 5, after the
combustors 1 are assembled to the gas turbine body. During
operation of the gas turbine, as shown in the blow-off area of FIG.
1, the seal piece 21 of the sealing apparatus 20 is pressed against
the wall surfaces of the seal grooves 5b under the differential
pressure between the casing 9 and the combustor 1 (see an open
thick arrow in the drawing), whereby leaking air (see thin arrows
in the drawing) between the adjacent outlet flange portions 5a is
sealed up.
[0037] On this occasion, the pair of sealing ridges 24 of the seal
piece 21 contact the wall surfaces of the adjacent seal grooves 5b
such that one sealing ridge contacts one wall surface. Thus, even
if displacement between the adjacent outlet flange portions 5a
occurs in the flowing direction of leaking air because of
deformation due to thermal expansion, the contact on the arcuate
surface is maintained, and wear or the like attributed to contact
of the edge portion is effectively avoided.
[0038] According to the present embodiment, as described above, the
sealing apparatus 20 can be realized which has a small number of
the components, whose production is easy, and which is wear
resistant. Thus, it has high sealing performance, and can achieve
cost reduction, and is optimal when used in a low NO.sub.x (premix)
combustor. Furthermore, the flexible sheet 23 can impart moderate
flexibility, thus making it possible to enhance assembly
characteristics within a narrow space.
[0039] The interposition of the metal foil 22 is not compulsory.
Instead of the spot welding W, other joining means, such as
brazing, may be employed.
Embodiment 2
[0040] FIG. 3 is a plan view of a sealing apparatus showing
Embodiment 2 of the present invention.
[0041] This is an embodiment in which the seal pieces 21 in
Embodiment 1 are arranged symmetrically on both surfaces of the
sheet 23. The sealing apparatus according to this embodiment can be
used as a sealing apparatus between the components when the flowing
direction of leaking air is reversed in the seal groove 5b.
Embodiment 3
[0042] FIG. 4 is a configurational drawing of a sealing apparatus
showing Embodiment 3 of the present invention.
[0043] This is an embodiment in which seal pieces 21A as in
Embodiment 1, formed by press-working to have sealing ridges 24A of
a semi-annular cross section, are laminated in a superposed manner
by spot welding W, and a plurality of the resulting laminates are
tied (connected) together in the longitudinal direction by two
wires 25. That is, each wire 25 is inserted into the circular hole
formed by the two sealing ridges 24A opposing each other.
[0044] According to the present embodiment, like Embodiment 1, the
sealing apparatus 20 can be realized which has a small number of
the components, whose production is easy, and which is wear
resistant. Thus, it has high sealing performance, and can achieve
cost reduction. Since the core material is the wire 25, moreover,
moderate flexibility can be imparted, and assembly characteristics
can also be enhanced.
[0045] While the present invention has been described by the above
embodiments, it is to be understood that the invention is not
limited to these embodiments, but may be varied in many other ways.
For example, the sealing apparatus according to the present
invention can be applied not only to a sealing apparatus at the
outlets of gas turbine combustors, but also to a sealing apparatus
for an assembly clearance between components for flow of other
fluid, or an assembly clearance between components involving
vibrations. Such variations are not to be regarded as a departure
from the spirit and scope of the invention, and all such
modifications as would be obvious to one skilled in the art are
intended to be included within the scope of the appended
claims.
* * * * *